Stepped helical scraper blade for ice cream maker

ABSTRACT

This invention discloses a mixing tool for an ice cream maker. The mixing tool is substantially helix-shaped and is disposed within the freezing chamber of an ice cream maker. The mixing tool serves a three-fold purpose. First, the mixing tool scrapes frozen ice cream mixture off of the walls of the freezing chamber. Second, the mixing tool is capable of whipping air into the ice cream mixture if the rate of rotation of the mixing tool is high. Third, the mixing tool urges frozen ice cream toward the dispensing valve of the freezing chamber.

BACKGROUND OF THE INVENTION

The making of ice cream in the home has been known for decades and hasremained popular in spite of the plethora of ice cream, frozen yogurtand other frozen confections commonly available at any grocery store. Asa result, many devices for the making of ice cream, frozen yogurt andother frozen confections in the home are well known in the art.

Such devices use a variety of methods to cool the ice cream mixture. Onesuch method involves placing the mixture in a vessel which is surroundedby a eutectic solution of water, ice and salt. The vessels are typicallyconstructed of a material known for its heat transfer capabilities, suchas aluminum. It is also well known to use a vessel with hollow wallswherein a eutectic material is housed. Such a vessel is typically placedinto a freezer until the eutectic material is frozen. The eutecticmaterial is then melted using heat drawn through the walls of the vesselfrom the ice cream mixture, thereby bringing the mixture to thetemperature necessary to freeze the mixture to the proper consistency.Such devices are shown in Cecchini (U.S. Pat. No. 4,643,583), Hapgood(U.S. Pat. No. 3,921,961) and Meyer et al. (U.S. Pat. No. 4,799,364).

It is also well known to use a device for scraping the frozen ice creammixture from the sides of the freezing vessel. Many different designs ofsuch devices, commonly referred to as "dashers, " are shown in the priorart. For example, Cecchini (U.S. Pat. No. 4,643,583), Beck (U.S. Pat.No. 4,732,013) and Eckel et al. (U.S. Pat. No. 5,106,199). Typically,the scraping of the frozen ice cream mixture is accomplished either byrotating the dasher within the freezing vessel or by rotating thefreezing vessel around a stationery dasher.

One problem associated with the making of soft serve ice cream isachieving the proper consistency. This is most commonly achieved byaerating the ice cream mixture as it is frozen. Thus, one barrier tomaking soft serve ice cream in the home is the cost associated with theapparatus used to aerate the mixture. As a result, soft serve ice creamis typically only available outside the home environment wherecommercial soft serve ice cream makers are available. Such devicestypically pump air into the freezing chamber in order to aerate themixture, to achieve the proper consistency for soft serve ice cream.Such devices are shown in Giannella et al. (U.S. Pat. No. 4,412,428),Schwitters et al. (U.S. Pat. No. 4,201,558) and Keyes et al. (U.S. Pat.No. 3,898,866).

Another problem associated with soft serve ice cream is the dispensingthereof. Unlike hard ice cream, which is typically scooped from acontainer and placed on a cone or in a bowl, soft serve ice cream isusually drawn from a machine using an extrusion-like process whereby thesoft serve ice cream is dispensed in a stream and piled up on a cone ina spiraled bee-hive shape. The cost of a machine capable of dispensingthe ice cream in this manner is another reason why soft serve ice creamis usually only available outside the home in a commercial setting.Typically, in commercial machines which freeze ice cream mixtures intosoft serve ice cream, the mixture is urged toward the extrusion orificeby the machine and is dispensed when a valve mechanism is opened. Thiscan be seen in Manfroni (U.S. Pat. No. 4,711,376) and Schwitters (U.S.Pat. No. 4,203,461). Alternatively, many commercial units are merelydispensing machines which dispense pre-made soft serve ice cream bydeforming a container thereof with a piston like device, as in Beach(U.S. Pat. No. 5,421,484), Montgomery et al. (U.S. Pat. No. 5,505,336)and Thomas (U.S. Pat. No. 5,405,054), or by urging the product towardthe outlet with compressed air, as in Broussalian (U.S. Pat. No.5,417,355).

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a soft serve icecream maker for domestic use that is capable of aerating the ice creammixture to the proper consistency. It is a further object of thisinvention to provide an ice cream maker capable of dispensing the icecream in the classic spiral beehive manner of commercial machines.Lastly, it is an object of this invention to provide these features in alow-cost, compact unit for at-home, table-top use.

Accordingly, the present invention provides an apparatus that meetsthese objectives. The preferred embodiment of the invention consistsprimarily of a vessel which serves as a freezing chamber, anauger-shaped dasher disposed therein, and a dispensing valve. Thevessel, where the ice cream mixture is mixed and frozen, iscylindrically shaped, being closed on one end and open at the other. Theauger-shaped dasher is disposed within the vessel and a dispensing valveassembly attaches to the open end of the vessel.

The vessel has an inner and an outer wall forming a sealed cavitytherebetween which is filled with a eutectic fluid. In the preferredembodiment, the inner wall is constructed of aluminum. The closed end ofthe vessel contains a journaled bearing which extends from the interiorof the vessel to the exterior of the vessel. The rotatable bearingengages the dasher on the inside of the vessel. The vessel is disposedin a horizontal position within a housing containing a motor. The motorengages the rotatable bearing on the exterior of the vessel in order torotate the dasher within the vessel.

The dasher disposed within the vessel has three purposes. First, thedasher scrapes the ice cream mixture off the inner wall of the vessel asit freezes thereon. Second, the speed and shape of the devicefacilitates the whipping of air into the ice cream mixture, in order toproduce the appropriate texture for soft serve ice cream. This isaccomplished by rotating the dasher at a much higher rate than one wouldnormally use for making hard ice cream (i.e., 100-130 rpm v. 45-50 rpm).Third, the dasher, aided by the horizontal orientation of the vessel,urges the frozen ice cream mixture toward the open end of the vesselwhere the dispensing valve is located.

The dispensing valve assembly serves to seal the open end of the vesselduring operation, to allow the unfrozen ice cream mixture to beintroduced into the vessel and to enable the convenient dispensing ofice cream directly into a dish or onto a cone when the freezing iscomplete.

The ice cream maker beeps after a suitable amount of time has elapsed,during which the ice cream mixture should have frozen into the properconsistency for soft serve ice cream, approximately thirty minutes.Thereafter, the ice cream maker beeps at two minute intervals to remindthe user that the ice cream is done. Eventually, the motor of the deviceautomatically turns off to avoid damage thereto by the load created bythe frozen ice cream.

The housing of the unit has two alternative preferred embodiments. Inone embodiment, the housing is supported above a table-top by a stand.The stand defines a drip tray underneath the dispensing orifice of thevalve assembly to catch spills and drips that occur while dispensing theice cream. In the alternative embodiment, the housing of the unit sitsat the edge of a table top and a drip tray is suspended over the side ofthe table. In this embodiment, the drip tray folds up and slidesunderneath the housing for storage.

In operation, the vessel is first placed into a freezer to freeze theeutectic fluid between the inner and outer walls. The dasher is engagedwith the rotating bearing located in the base of the vessel and thevalve assembly is attached to the open end of the vessel. The vessel isplaced in a horizontal orientation within the housing, with the portionof the rotatable bearing exterior to the vessel engaged with the motor.The ice cream mixture is then introduced into the vessel, and the unitis turned on, thereby rotating the dasher at approximately 120 rpm. Uponreaching the desired frozen consistency, the device beeps, and the icecream may be dispensed via the valve assembly. Thereafter, the vesselmay be removed from the housing by depressing a button which releases aspring-loaded detent mechanism that pushes the vessel and attached valveassembly out of the housing for cleaning, storage and refreezing of theeutectic fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the exterior of the device in perspective view.

FIG. 2 shows a top plan view of the device.

FIG. 3 shows a cross-sectional view of the device along line 3--3 ofFIG. 2.

FIG. 4 shows a side elevational view of the device.

FIG. 5 shows a cross-sectional view along line 5--5 of FIG. 4.

FIG. 6 shows a perspective view of an alternate embodiment of theexterior housing of the device.

FIG. 7 shows a side elevational view of the alternate embodiment of theexterior of the device of FIG. 6.

FIG. 8 shows an exploded view of the freezing vessel of the device.

FIG. 9 shows a top view of the freezing vessel of the device.

FIG. 10a shows a cross sectional view of the freezing vessel along line10a--10a of FIG. 9, with an enlarged detail of the bearing of the deviceshown in FIG. 10b.

FIG. 11 shows an exploded view of the bearing of the device.

FIG. 12 shows the bearing of FIG. 11 assembled in perspective view.

FIG. 13a shows a side elevational view of the bearing of FIG. 11.

FIG. 13b shows a bottom view of the bearing of FIG. 11.

FIG. 14a shows a top view of the bearing of FIG. 11.

FIG. 14b shows a cross-sectional view of the bearing along line 14b--14bof FIG. 14a.

FIG. 15 shows the valve assembly in perspective view.

FIG. 16 shows the valve assembly in an exploded view.

FIG. 17a shows a front elevational view of the valve assembly.

FIG. 17b shows a side elevational view of the valve assembly.

FIG. 17c shows a rear elevational view of the valve assembly.

FIG. 18a shows a top plan view of the valve assembly.

FIG. 18b shows a side elevational view of the valve assembly.

FIG. 18c shows a bottom plan view of the valve assembly.

FIG. 19a shows a front elevational view of the shaft member.

FIG. 19b shows a right elevational view of the valve member.

FIG. 19c shows a rear elevational view of the shaft member.

FIG. 20 shows one embodiment of the circuit of the device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is described with respect to the preferredphysical embodiments constructed in accordance herewith. It will beapparent to those of ordinary skill in the art that variousmodifications and improvements may be made without departing from thescope and spirit of the invention. Accordingly, the invention is notlimited by the specific embodiments illustrated and described, but onlyby the scope of the appended claims including all equivalents thereof.

In addition, although the preferred embodiment of this invention refersto a soft serve ice cream maker, it is recognized that the device can bemade to work with any frozen food. Furthermore, certain aspects of thisinvention are applicable to other types of appliances which may notnecessarily deal with the freezing of food or ice cream mixtures.Therefore, any and all references to "ice cream" or "ice cream mixture"is intended to include , inter alia, true ice cream, as well as icemilk, frozen yogurt, sorbet, other frozen confections and any type ofmixture with which such an appliance as that disclosed herein would beused. Furthermore, as used herein, the term "soft serve" is intended tomean a frozen or partially or semi-frozen confection which is madeflowable by air entrainment and/or agitation. Additionally, the term"dasher" is intended to mean any tool disposed within a vessel thatperforms a mixing, scraping, whipping, chopping or beating function.

Shown generally in FIGS. 1 and 6 are alternate embodiments of the deviceas a whole. FIG. 1 shows housing 10 mounted on stand 8. Stand 8 isequipped with an integral drip pan 20, which will catch drippings fromdispensing orifice 18. FIG. 6 shows an alternate embodiment whereinhousing 10 sits on a counter top near the edge thereof, and drip pan 20hangs over the side of the counter top suspended by drip pan support 22.The embodiments of FIGS. 1 and 6 both use an identical housing 10 andmay be configured as in either FIG. 1 or FIG. 6. Shown also in FIGS. 1and 6 are on/off switch 12, release button 14, fill cap 16 anddispensing orifice 18, all of which will be described in greater detailbelow.

The vessel 30, shown in FIG. 8, in which the mixture is frozen ishorizontally disposed within housing 10. As best shown in FIG. 3, vessel30 has outer wall 42 and inner wall 44 forming cavity 34 therebetween.Vessel top 40, shown in FIG. 8, is integral with inner wall 44 and formsa seal with outer wall 42. Inner wall 44, a heat exchange surface, andvessel top 44 are, in the preferred embodiment, integrally constructedof aluminum, but can be constructed of any heat conducting material andneed not be integral with each other.

A eutectic solution is disposed within cavity 34 shown in FIG. 3. Inoperation, the eutectic fluid is frozen by placing vessel 30 into afreezer. The eutectic fluid only fills approximately eighty to ninetypercent of cavity 34 to allow room within cavity 34 for expansion of theeutectic fluid as it freezes. The purpose of the eutectic fluid is todraw heat from inner wall 42, which in turn draws heat from the mixturedisposed within vessel 30. The propagation of heat from the mixture tothe eutectic fluid through inner wall 44 causes the frozen eutecticfluid to melt and the mixture to freeze. This process is aided bywebbing 32 in FIG. 8 which is disposed within cavity 34. Webbing 32, inthe preferred embodiment, consists of a piece of corrugated aluminum,but may be constructed from any heat conducting material. Webbing 32contacts the outer surface of inner wall 44 shown in FIG. 10(a) and aidsin the distribution of heat from inner wall 44 to the eutectic fluid. Inthe preferred embodiment, the eutectic fluid consists mainly of sodiumpolysaccharide, but may consist of any eutectic fluid well known bythose skilled in the art.

Dasher 80, as best shown in FIG. 8 is disposed within vessel 30. Dasher80 consists essentially of a substantially helix-shaped scraper blade 82which is supported by a support structure consisting of upper and lowerhubs 84 and 86 respectively, connected by a plurality of structuralmembers 88. The purpose of dasher 80 is to scrape frozen mixture off ofinner wall 44, to whip air into the mixture and to urge the frozenmixture towards the open end of vessel 30. It should be noted that noexternal source of air is present in the preferred embodiment. Dasher 80whips the ambient air within vessel 30 into the mixture to aerate it.Although hubs 84 and 86 are circular in the preferred embodiment, it canbe seen that they can be of any convenient shape. Additionally, in thepreferred embodiment, four structural members 88 are used, but it can beseen that the number and shape of structural members 88 can vary.Although the main purpose of structural members 88 is to support blade82, they also serve to aid in the aeration of the mixture as dasher 80is rotated within vessel 30.

The pitch of helix-shaped scraper blade 82 changes at point 89 in FIG.8. The purpose of the pitched helix-shape of scraper blade 82 istwo-fold. First, the purpose of the portion of the helix with thegreater pitch, below point 89, is to urge the semi-frozen producttowards the open end of vessel 30. The purpose of the portion of thehelix with a lesser pitch, above point 89, is to force the semi-frozenproduct out of vessel 30 through the outlet opening 60, shown in FIG.17c.

In FIG. 8 the flat step areas 83 of blade 82, also have a two-foldpurpose. First, steps 83 add to the turbulent flow of fluid withinvessel 30, thereby aiding in the aeration of the mixture. Second, steps83 allow dasher 80 to be molded from a single piece of plastic whilekeeping the cross sectional area of blade 82 constant. Without steppedareas 83, the cross sectional area of blade 82 would have to beincreased at the points of intersection with structural members 88 toallow the dasher 80 to be removed from its mold. The increasedcross-sectional areas required when blade 82 is molded without steppedareas 83 requires a longer cooling time after the injection of moltenplastic into the mold before the molded piece can be removed therefrom,thereby resulting in an increased cost of manufacturing. Thus, thestepped areas 83 also serve to allow the dasher 80 to be molded as asingle piece in an economically feasible manner.

Rod 90, as shown in FIGS. 3, 15, 17(b) and 18(b) and (c), is positionedwithin the center area of dasher 80, offset from the center of vessel30. Rod 90 is stationary, being seated on one end in seat 92, shown inFIGS. 3 and 10(a) and (b), and held in place at the other end by valveassembly 50 best shown in FIG. 15 . Rod 90 serves to deflect frozenmixture from the center of vessel 30 to the area of vessel 30 which isswept by helical blade 82 as it rotates, such that the frozen mixturecan be urged forward toward the outlet hole 60 by helical blade 82. Rod90 also adds to the turbulent fluid flow within vessel 30, thus aidingin the aeration process.

In the preferred embodiment, dasher 80 is rotated within vessel 30 at anaverage speed of approximately 120 revolutions per minute, although thisaverage speed can range from about 100 to about 130 revolutions perminute with the same results. Dasher 80 will rotate more slowly as themixture within vessel 30 becomes thicker as it freezes.

Dasher 80 is rotated by geared motor 99, as shown in FIG. 3, which ismounted within housing 10. Dasher 80 is coupled to motor 99 viajournaled bearing 68, which extends through the base of vessel 30. Asshown in FIGS. 11, 12, 13(a), 13(b), 14(a), and 14(b), bearing 68consists of flange 74 and gasket 72, which are held in place on theinterior of vessel 30 by retaining ring 78 which is positioned on theexterior of the base of vessel 30 and held in place by the threads offlange 74. Flange 74, gasket 72 and retaining ring 78 thereby form afluid-tight seal. Spindle 76 extends through the hole in flange 74 andsecures shoulder 71 in place. Shoulder 71 contains a polygonal,frustum-shaped boss 70 which extends therefrom. Boss 70 engages recess85 shown in FIGS. 10(a) and (b) defined in the center of lower hub 86 ofdasher 80, as shown in FIGS. 3 and 10, to rotate dasher 80 within vessel30. Boss 70 and recess 85 may be of any shape which will allow boss 70to rotate dasher 80. Spindle 80 engages ball gear 97 shown in FIGS.13(a) and (b) on the exterior of vessel 30, which in turn engages acoupling collar with ribs (not shown) which is attached to geared motor99, thereby allowing vessel 30 to be easily coupled to motor 99 as it isinserted into housing 10. In FIG. 3 air holes 4 in the rear of housing10 serve to cool motor 99 as it rotates. On/off switch 12 is used toturn motor 99 on and off.

Valve assembly 50 is shown in FIGS. 15 and 16. Valve assembly 50 isconnected to and seals vessel 30 at the open end thereof. A plurality ofhooks 37, best seen in FIG. 16, on the rear of valve assembly 50 engagea corresponding plurality of ribs 36 on the outer wall 42 of vessel 30,shown in FIG. 8, to hold valve assembly 50 in place.

In FIG. 16 molded gasket 63 fits in groove 38 of FIG. 8 of vessel top40. Groove 38 and gasket 63 engage raised rib 65 defined on the rear offaceplate 51 of valve assembly 50, best shown in FIG. 17c, to make theseal between vessel 30 and valve assembly 50 fluid tight.

Guiding ring 67, also defined on the rear of faceplate 51 and shown inFIG. 17c, serves to keep dasher 80 in place as it rotates within vessel30 by engaging upper hub 84 of dasher 80 when valve assembly 50 is inplace.

Valve assembly 50 serves to allow a pourable mixture to be introducedinto vessel 30 and also facilitates the dispensing of the semi-frozenproduct after the freezing process is complete. Valve assembly 50consists of valve assembly housing 64, which includes faceplate 51, andintegral shaft 52 attached thereto as shown in FIG. 16. Inlet opening 58and outlet opening 60 extend through the wall of shaft 52 and the wallof faceplate 51, as shown in FIG. 17(c) and FIG. 3.

Shaft member 54 is disposed within shaft 52. Shaft member 54 has ahollow interior defining two chambers, an upper chamber and a lowerchamber. In the upper chamber is defined inlet opening 59 whichcorresponds to inlet opening 58 defined in faceplate 51 and shaft 52.The lower chamber defines outlet opening 61 which corresponds to outletopening 60 defined in faceplate 51 and shaft 52. Inlet and outletopenings 59 and 60 respectively can best be seen in FIGS. 19a-c. Theupper chamber allows communication between fill opening 56 and theinterior of vessel 30 through inlet openings 58 and 59, and the lowerchamber allows communication between vessel 30 and dispensing orifice 18via outlet openings 60 and 61.

When shaft member 54 is disposed in shaft 52, it can be rotated thereinto a fill position, a sealing position or a dispensing position. When inthe fill position, inlet opening 59 in shaft member 54 is aligned withinlet opening 58 defined in faceplate 51 and shaft 52, thereby allowingcommunication between fill opening 56 and the interior of vessel 30 viathe upper chamber of shaft member 54. In order to fill the interior ofthe vessel with pourable mixture, fill cap 16 seen in FIGS. 16 and17(a),(b), and (c) is pivoted on rivet 17, seen in FIG. 16, to allowaccess to fill opening 56. Pourable mixture is poured through opening56, through the upper chamber of shaft member 54 and through inletopenings 58 and 59, into the interior of vessel 30. In the preferredembodiment, inlet openings 58 and 59 are large enough such that theambient air within vessel 30 can escape through fill opening 56 viainlet openings 58 and 59 as the mixture is poured in. When shaft member54 is in the fill position, outlet opening 60 is sealed by the wall ofshaft member 54.

When shaft member 54 is rotated to the sealed position, inlet opening 58and outlet opening 60 are sealed by the wall of shaft member 54.

When in the dispense position, shaft member 54 is rotated such thatoutlet opening 61 of shaft member 54 is aligned with outlet opening 60defined in faceplate 51 and shaft 52, to allow communication between theinterior of vessel 30 and dispensing orifice 18 via the lower chamber ofshaft member 54. When shaft member 54 is in the dispense position, inletopening 58 is sealed by the wall of shaft member 54.

The valve assembly housing is covered by decorative cover 66. Dispensingorifice 18 is covered by extrusion die 19, which defines thecross-sectional shape of the semi-frozen product as it is dispensed fromvessel 30. Although shown in FIG. 18c as being star-shaped, extrusiondie 19 could define any shape.

Outlet opening 60, defined in faceplate 51 and shaft 52, is partiallysurrounded by bevel 62 on the side which faces the interior of vessel30, to aid helical blade 82 in guiding the semi-frozen product out ofvessel 30. Bevel 62 is best shown in FIG. 17c.

Valve assembly 50 is fitted to vessel 30 prior to vessel 30 beinginserted into housing 10. As the assembled vessel 30 and valve assembly50 are inserted into housing 10, they are met with resistance by leafsprings 48, as shown in FIG. 3. When vessel 30 has been inserted farenough into housing 10, latch 15, shown in FIG. 3, engages one of aplurality of detents 46 defined in the outer wall 42 of vessel 30. Thedetents are best shown in FIG. 8. To release the vessel 30 from housing10, release button 14 is pressed, thus removing latch 15 from detent 46.Leaf springs 48 then force vessel 30 out of housing 10. It is immaterialwhich one of the plurality of detents 46 is engaged by latch 15. Thevessel 30 and attached valve assembly 50 should be rotated as they areinserted into housing 10 until valve assembly 50 is properly alignedwith the outside of housing 10. Due to the position of ribs 36 and hooks37, when valve assembly 50 is properly aligned with the exterior ofhousing 10, one of the detents 46 will be engaged by latch 15.

In the embodiment of the device shown in FIG. 6, wherein drip pan 20 issuspended over the edge of a counter top by support member 22, drip tray20 and support member 22 may be folded up and stored under housing 10.As best seen in FIG. 7, in this configuration, drip pan 20 and supportmember 22 are suspended from housing 10 by a pair of pins 25 whichextend from the top of support member 22 and engage track 26 on theunderside of housing 10. Drip pan 20 and drip pan support 22 can berotated upwardly and slid under the housing 10 on the tracks for storagepurposes. When in this position, drip pan support 22 will be underneathhousing 10 and drip pan 20 will be adjacent to valve assembly 50. In theembodiment of FIG. 6, housing 10 is supported on a counter top by aplurality of feet 6, as shown in FIG. 7.

The device of this invention also contains an alarm that informs theuser when the mixture has reached the proper frozen consistency. In oneembodiment of this alarm, a timer is started when on/off switch 12 ispressed. After thirty minutes has elapsed an alarm is sounded via apiezo electric transducer (SP1 of FIG. 20). Thereafter, the alarm issounded again at two minute intervals until a total time of forty-fiveminutes has elapsed since the pressing of on/off switch 12. Although thepreferred embodiment uses the above specified timed intervals at whichto sound the alarm, it is recognized that any convenient interval oftime may be used.

In another embodiment of the alarm, samples of the current drawn bymotor 99 are taken at predetermined intervals after the on/off switch 12has been pressed. It has been noted that motor 99 draws its peak currentat the same time that the semi-frozen mixture reaches its peakconsistency for serving. Thereafter, the current drawn by motor 99begins to decrease. The alternative embodiment of the alarm feature,therefore, senses when motor 99 has drawn its peak current by noting therise of the amount of current drawn by motor 99 via the samples whichare taken at timed intervals, and sounding an alarm when the amount ofcurrent drawn by motor 99 starts to decrease. After the initial alarmhas sounded, the alarm will again be sounded at timed intervalsthereafter, every 2 minutes in the preferred embodiment, until the motoris eventually shut off after a predetermined time, approximately 15minutes after the first alarm has been sounded. In either embodiment,the motor can be restarted by pressing on/off switch 12.

A sample circuit implementing the first embodiment of the alarm is shownin FIG. 20. The circuit uses an 8 pin microcontroller, such as MicrochipTechnologies part number PIC12C508, to implement the logic functions ofthe alarm. Power is toggled to the motor via triac Q1 when on/off switchSW1 is pressed. When switch SW1 is initially pressed, thirty minute anda forty-five minute timers are started. When the thirty minute timer haselapsed, a 4 Khz beep is sent to piezo electric transducer SP1. Thisbeep is sent to SP1 at two minute intervals until the forty-five minutetimer has elapsed, at which time power to the motor is toggled off.Power for the circuit is provided by a half-wave rectifier and zenerregulator circuit powered from a 120 v AC power line.

I claim:
 1. A dasher for a food processing device comprising:(a) anupper hub; (b) a lower hub; (c) a plurality of support members extendingfrom said upper hub to said lower hub, said support members disposedaround the perimeter of said upper and lower hubs at spaced intervals;(d) a stepped helix member disposed around said plurality of supportmembers and extending from said lower hub to said upper hub, said helixmember having flat steps where said helix member intersects said supportmembers.
 2. The device of claim 1 wherein said stepped helix has a firstend adjacent to said lower hub and a second end adjacent to said upperhub, and first and second pitches, and wherein said helix has a firstpitch starting at said first end and wherein said first pitch changes tosaid second pitch at a point between said first end and said second end.3. The device of claim 2 wherein said point is more than one completerevolution from said second end of said stepped helix.
 4. The device ofclaim 1, 2 or 3 wherein said dasher is plastic.
 5. The device of claim1, 2 or 3 wherein said dasher is injection molded as a single piece. 6.The device of claim 1, 2 or 3 wherein said dasher defines a recess insaid lower hub.